DOI QR코드

DOI QR Code

Genetic Structure and Composition of Genetic Diversity in the Kouchi Sub-breed of the Japanese Brown Cattle Population

  • Honda, Takeshi ;
  • Fujii, Toshihide ;
  • Mukai, Fumio
  • Received : 2007.02.13
  • Accepted : 2007.06.18
  • Published : 2007.11.01

Abstract

Japanese Brown cattle, one of the four domestic beef breeds in Japan, are suffering from numerical reduction due to economic pressure from profitable breeds. In this study, all the reproductive cows in the Kouchi sub-breed of the Japanese Brown cattle that were alive in July 2005 were investigated by pedigree analysis to clarify genetic structure and composition of genetic variability. In addition, genetically important individuals for the maintenance of genetic variability of the sub-breed were also identified through the core set method. The number of cows analyzed was 1,349. Their pedigrees were traced back to ancestors born around 1940, and pedigree records of 13,157 animals were used for the analysis. Principal component analysis was performed on the relationship matrix of the cows, and their factor loadings were plotted on a three-dimensional diagram. According to their spatial positions in the diagram, all the cows were subdivided into five genetically distinctive subpopulations of 131 to 437 animals. Genetic diversity of the whole sub-breed, which is estimated to be 0.901, was decomposed into 0.856 and 0.045 of within-subpopulation and between-subpopulation components. Recalculation of genetic diversity after removal of one or several subpopulations from the five subpopulations suggested that three of them were genetically important for the maintenance of genetic variability of the sub-breed. Applying the core set method to all the cows, maximum attainable genetic diversity was estimated to be 0.949, and optimal genetic contributions assigned to each cow supported the previous results indicating relative importance of the three subpopulations as useful genetic materials.

Keywords

Genetic Diversity;Genetic Structure;Japanese Brown;Pedigree Analysis;Principal Component Analysis

References

  1. Oyama, K., M. Nojima, M. Shojo, M. Fukushima, K. Anada and F. Mukai. 2007. Effect of sire mating patterns on future genetic merit and inbreeding in a closed beef cattle population. J. Anim. Breed. Genet. 124:73-80. https://doi.org/10.1111/j.1439-0388.2007.00638.x
  2. Wright, S. 1951. The genetical structure of populations. Ann. Eugen. 15:323-354.
  3. Wright, S. 1969. Evolution and the Genetics of Populations. vol. 2. The Theory of Gene Frequencies. University of Chicago Press, Chicago.
  4. Caballero, A. and M. A. Toro. 2002. Analysis of genetic diversity for the management of conserved subdivided populations. Conserv. Genet. 3:289-299. https://doi.org/10.1023/A:1019956205473
  5. Frankham, R., J. D. Ballou and D. A. Briscoe. 2002. Introduction to Conservation Genetics. Cambridge University Press, Cambridge.
  6. Nei, M. 1973. Analysis of gene diversity in subdivided populations. Proc. Natl. Acad. Sci. USA. 70:3321-3323. https://doi.org/10.1073/pnas.70.12.3321
  7. Nei, M. 1987. Molecular Evolutionary Genetics. Columbia University Press, New York.
  8. Nomura, T., T. Honda and F. Mukai. 2005. Monitoring and preservation of genetic diversity in livestock breeds: a case study of the Japanese Black cattle population. Curr. Top. Genet. 1:59-71.
  9. Theodorou, K. and D. Couvet. 2006. On the expected relationship between inbreeding, fitness, and extinction. Genet. Sel. Evol. 38:371-388. https://doi.org/10.1186/1297-9686-38-4-371
  10. Eding, H., R. P. M. A. Crooijmans, M. A. M. Groenen and T. H. E. Meuwissen. 2002. Assessing the contribution of breeds to genetic diversity in conservation schemes. Genet. Sel. Evol. 34:613-633. https://doi.org/10.1186/1297-9686-34-5-613
  11. Barker, J. S. F. 2001. Conservation and management of genetic diversity: a domestic animal perspective. Can. J. For. Res. 31:588-595. https://doi.org/10.1139/cjfr-31-4-588
  12. Petit, R. J., A. El Mousadic and O. Pons. 1998. Identifying populations for conservation on the basis of genetic markers. Conserv. Biol. 12:844-845. https://doi.org/10.1046/j.1523-1739.1998.96489.x
  13. Honda, T., T. Fujii, T. Nomura and F. Mukai. 2006. Evaluation of genetic diversity in Japanese Brown cattle population by pedigree analysis. J. Anim. Breed. Genet. 123:172-179. https://doi.org/10.1111/j.1439-0388.2006.00586.x